Solve for $x$ and $y$ using substitution. ${3x-6y = -12}$ ${y = -x-1}$
Since $y$ has already been solved for, substitute $-x-1$ for $y$ in the first equation. ${3x - 6}{(-x-1)}{= -12}$ Simplify and solve for $x$ $3x+6x + 6 = -12$ $9x+6 = -12$ $9x+6{-6} = -12{-6}$ $9x = -18$ $\dfrac{9x}{{9}} = \dfrac{-18}{{9}}$ ${x = -2}$ Now that you know ${x = -2}$ , plug it back into $\thinspace {y = -x-1}\thinspace$ to find $y$ ${y = -}{(-2)}{ - 1}$ $y = 2 - 1$ $y = 1$ You can also plug ${x = -2}$ into $\thinspace {3x-6y = -12}\thinspace$ and get the same answer for $y$ : ${3}{(-2)}{ - 6y = -12}$ ${y = 1}$